Operation tool for fluid injector using multi-microneedle device

ABSTRACT

An operation tool for a fluid injector includes a selective movement mechanism which moves the fluid injector between a first protruding position and a second protruding position in a housing of an outer cylinder. When the fluid injector is at the first protruding position, microneedles of a multi-microneedle device are protruded out to a first distance from the first open end. When the fluid injector is at the second protruding position to discharge a fluid via the microneedles, the microneedles are protruded out to a second distance from the first open end, which is shorter than the first distance. The selective movement mechanism includes a rotational-linear movement conversion mechanism which moves the fluid injector between the first and second protruding positions along a longitudinal center line of the outer cylinder based on a direction and an amount of rotation of the outer cylinder relative to the fluid injector.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No. 14/689,541, filed Apr. 17, 2015, which is a continuation of International Application No. PCT/JP2013/071722, filed Aug. 9, 2013, which is based upon and claims the benefits of priority to Japanese Application No. 2012-229581, filed Oct. 17, 2012. The entire contents of all of the above applications are incorporated herein by reference.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to an instrument for operating a fluid injector that uses a multi-microneedle device.

Discussion of the Background

Fluid injectors which use a multi-microneedle device are well known, for example, in the medical field. Such a fluid injector is known as a syringe in the medical field.

A fluid injector is provided with a fluid retention barrel (syringe barrel of a syringe) which includes a long fluid retention space that can retain a given amount of fluid (e.g., medicinal solution in the medical field), a fluid outlet nozzle which is arranged at an end in a longitudinal direction of the fluid retention space and able to discharge the fluid from the fluid retention space, and a fluid retention space inlet opening which is arranged at the other end in a longitudinal direction of the fluid retention space. The fluid injector is further provided with a piston member which is slidably assembled into the fluid retention space of the fluid retention barrel along a center line in the longitudinal direction via the fluid retention space inlet opening.

It is considered recently in the medical field to use a multi-microneedle device, in place of a single injection needle well known in the medical field, for conducting intradermal injection, with the device being mounted to the fluid outlet nozzle of the injection barrel of a conventional syringe. The multi-microneedle device is provided with a body that is formed with an outlet nozzle mounting nozzle which is detachably mounted to a fluid outlet nozzle of a syringe barrel to discharge a fluid (medicinal solution in the medical field), and a fluid retention space which temporarily retains the fluid that has been discharged to the outlet nozzle mounting nozzle from the fluid outlet nozzle of the syringe barrel by the pressing force of the piston member of the syringe. The multi-microneedle device is further provided with a plurality of microneedles which are arranged on a plane of the body, the plane being located on an opposite side of the outlet nozzle mounting nozzle, being intervened by the fluid retention space.

The plane of the body functions as a skin contact surface. Each of the plurality of microneedles has a microscopic fluid injection channel which is extended from a base end on the plane to a tip that is apart from the plane. In each of the plurality of the microneedles, the length between the base end and the tip (i.e. the height of each microneedle) is set so as to fall within a range of the thickness of a skin tissue, against which the microneedles are used, of an organism (e.g., any human being) possessing the skin tissue.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, an operation tool for a fluid injector, includes an outer cylinder having a first open end, a second open end, and a housing extended between the first open end and the second open end, the housing being formed such that a fluid injector having a multi-microneedle device is movable in the housing along a longitudinal center line of the fluid injector, and a selective movement mechanism which moves the fluid injector between a first protruding position and a second protruding position in the housing of the outer cylinder. The selective movement mechanism is structured such that, when the fluid injector is at the first protruding position, microneedles of the multi-microneedle device is protruded out to a first distance from the first open end, and that when the fluid injector is at the second protruding position to discharge a fluid from the fluid injector via the microneedles, the microneedles are protruded out to a second distance from the first open end, the second distance being shorter than the first distance. The selective movement mechanism includes a rotational-linear movement conversion mechanism which is interposed between the outer cylinder and the fluid injector, and moves the fluid injector between the first protruding position and the second protruding position along a longitudinal center line of the outer cylinder based on a direction and an amount of rotation of the outer cylinder relative to the fluid injector.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:

FIG. 1 is a schematic vertical cross-sectional view illustrating an operation tool according to an embodiment, for a fluid injector that uses a multi-microneedle device, the view specifically illustrating a fluid injector that uses a multi-microneedle device, with a plurality of microneedles of the multi-microneedle being arranged at a first protruding position, in an outer cylinder of the operation tool;

FIG. 2 is a schematic vertical cross-sectional view illustrating the operation tool according to the embodiment, for a fluid injector that uses a multi-microneedle device, the view specifically illustrating a fluid injector that uses a multi-microneedle device, with the plurality of microneedles of the multi-microneedle being arranged at a second protruding position, in the outer cylinder of the operation tool;

FIG. 3 is a schematic vertical cross-sectional view illustrating an operation tool according to a modification of the embodiment, for a fluid injector that uses a multi-microneedle device, the view specifically illustrating a fluid injector that uses a multi-microneedle device, with a plurality of microneedles of the multi-microneedle being arranged at a first protruding position, in an outer cylinder of the operation tool; and

FIG. 4 is a schematic vertical cross-sectional view illustrating the operation tool according to the modification of the embodiment, for a fluid injector that uses a multi-microneedle device, the view specifically illustrating a fluid injector that uses a multi-microneedle device, with the plurality of microneedles of the multi-microneedle being arranged at a second protruding position, in the outer cylinder of the operation tool.

DESCRIPTION OF THE EMBODIMENTS

The embodiments will now be described with reference to the accompanying drawings, wherein like reference numerals designate corresponding or identical elements throughout the various drawings.

First Embodiment

With reference to FIGS. 1 and 2, hereinafter is schematically described a configuration of an operation tool 14 according to an embodiment, for a fluid injector 12 that uses a multi-microneedle device 10.

The fluid injector 12 using the multi-microneedle device 10 which is operated by the operation tool 14 according to the embodiment is recently considered to be used, for example, in the medical field as a syringe.

The fluid injector 12 is provided with a fluid retention barrel 12 b (syringe barrel of a syringe) which includes a long fluid retention space that can retain a given amount of a fluid (e.g., medicinal solution in the medical field), a fluid outlet nozzle 12 a which is located at a longitudinal end of the fluid retention space and enables discharge of the fluid from the fluid retention space, and a fluid retention space inlet opening which is located at the other longitudinal end of the fluid retention space. The fluid injector 12 is further provided with a piston member 12 c which is slidably assembled into the fluid retention space of the fluid retention barrel 12 b along the longitudinal center line via the fluid retention space inlet opening.

It is considered recently in the medical field to use the multi-microneedle device 10, in place of a single injection needle well known in the medical field, for intradermal injection, with the device being mounted to the fluid outlet nozzle of the injection barrel of a conventional syringe.

The multi-microneedle device 10 is provided with a body 10 b that is formed with: an outlet nozzle mounting nozzle 10 a which is detachably mounted to the fluid outlet nozzle 12 a of the fluid retention barrel 12 b of the fluid injector 12 (the syringe barrel of a syringe) to discharge a fluid (medicinal solution in the medical field); and a fluid retention space which temporarily retains the fluid that has been discharged to the outlet nozzle mounting nozzle 10 a from the fluid outlet nozzle 12 a of the fluid retention barrel 12 b by the pressing force of the piston member 12 c of the fluid injector 12. The multi-microneedle device 10 is further provided with a plurality of microneedles 10 c which are arranged on a surface (a plane in the present embodiment) of the body 10 b, the surface being located on an opposite side of the outlet nozzle mounting nozzle 10 a, being intervened by the fluid retention space.

The multi-microneedle device 10 can be fabricated, for example, by applying an etching process that uses a known photolithography method to a silicon substrate. Further, using the multi-microneedle device made of silicon as an original plate, an inverted replicated plate can be formed using electroforming, and using the replicated plate, a multi-microneedle device made of a resin can be fabricated.

Preferably, at least the plurality of microneedles 10 c of the multi-microneedle device 10 are formed of a biocompatible material. More preferably, the multi-microneedle device 10 as a whole is formed of a biocompatible material. Such biocompatible materials include: metal that contains stainless steel, titanium, manganese, and the like; resins that contain medical silicone, polylactic acid, polyglycolic acid, polycarbonate, and the like; and inorganic materials, such as silicon.

The biocompatible resin materials as mentioned above can be subjected to a known molding technique, such as injection molding, imprinting, hot embossing, or the like, and processed into at least the plurality of microneedles 10 c of the multi-microneedle device 10, or into the entire multi-microneedle device 10.

Each of the plurality of microneedles 10 c has a microscopic fluid injection channel which extends from a base end on the plane to a tip that is apart from the plane. In each of the plurality of the microneedles 10 c, the length between the base end and the tip, i.e. the height of each microneedle 10 c, is set so as to fall within a range of the thickness of the skin tissue of an organism (e.g., any human being) possessing the skin tissue that is a target of using the needles, preferably within a range of the thickness of the skin tissue not including nerves. Specifically, it is preferable that the height of each microneedle 10 c is set within a range of 100 μm to 2000 μm.

The overall shape of each of the plurality of microneedles 10 c may be a cone shape including a circular cone or a pyramid, or may be a circular columnar or square columnar shape with its tip portion being in a conical or pyramidal shape. The microscopic fluid discharge channel can be formed in each of the plurality of microneedles 10 c through a known microhole drilling process by means of, for example, a micro drill, a laser beam, or the like.

The plurality of microneedles 10 c can be arrayed on the plane of the body 10 b in a grid-like, concentric or random manner, or the like, according to the purpose of use.

The operation tool 14 according to the present embodiment is provided with an outer cylinder 16 that includes a one-end opening 16 a, an other-end opening 16 b, and a fluid injector housing space 16 c which is extended between the one-end opening 16 a and the other-end opening 16 b, and holds the fluid injector 12 that uses the multi-microneedle device 10 so as to be movable along a longitudinal center line of the fluid injector 12.

The operation tool 14 according to the present embodiment is further provided with a selective movement mechanism 18 that moves the fluid injector 12 between a first protruding position and a second protruding position in the injector housing space 16 c of the outer cylinder 16.

At the first protruding position, the fluid injector 12 is able to have the microneedles 10 c of the multi-microneedle device 10, as shown in FIG. 1, out to an external space by a first distance from the one-end opening 16 a of the outer cylinder 16.

At the second protruding position, the fluid injector 12 is able to have the microneedles 10 c of the multi-microneedle device 10, as shown in FIG. 2, out to an external space by a second distance, which is shorter than the first distance mentioned above, from the one-end opening 16 a of the outer cylinder 16.

In the operation tool 14 according to the present embodiment, the fluid is discharged at the second position from the fluid injector 12 via the plurality of microneedles 10 c of the multi-microneedle device 10.

In the present embodiment, the outer cylinder 16 has one-end face in which the one-end opening 16 a is open, the one-end face functioning as a skin contact surface 16 d. It is preferable that the skin contact surface 16 d is processed so as to be slidable relative to the surface of the skin of an organism without generating a large frictional force.

The selective mechanism 18 of the operation tool 14 according to the present embodiment includes a rotational-linear movement conversion mechanism 20 which is interposed between the outer cylinder 16 and the fluid injector 12 to move the fluid injector 12 between the first position shown in FIG. 1 and the second position shown in FIG. 2 along the longitudinal center line of the outer cylinder 16, in conformity with the direction and amount of the rotation of the outer cylinder 16 relative to the fluid injector 12.

In the present embodiment, the rotational-linear movement conversion mechanism 20 includes an internal threaded portion 20 a which is provided to an inner surface of a peripheral wall of the outer cylinder 16, and an external threaded portion 20 b which is provided to the fluid injector 12 for threadable engagement with the internal threaded portion 20 a of the outer cylinder 16.

In the present embodiment, the internal threaded portion 20 a can be integrally formed with the peripheral wall of the outer cylinder 16.

More specifically, the selective movement mechanism 18 is provided with a cylindrical intermediate member 18 a having a one-end opening and an other-end opening, and arranged between an outer peripheral wall of the outer cylinder 16 and an outer peripheral wall of the fluid retention barrel 12 b of the fluid injector 12 (syringe barrel of a syringe) that is accompanied by the multi-microneedle device 10. The one-end opening of the intermediate member 18 a is fixed with an outer peripheral surface of the body 10 b of the multi-microneedle device 10 of the fluid injector 12. The fluid injector 12, which is connected to the multi-microneedle device 10, is housed in a columnar space extending from the one-end opening to the other-end opening of the intermediate member 18 a. The intermediate member 18 a is permitted to be movable in the fluid injector housing space 16 c of the outer cylinder 16 together with the fluid injector 12, which is accompanied by the multi-microneedle device 10, relative to the longitudinal center line of the outer cylinder 16. The intermediate member 18 a has an outer peripheral wall which is provided with the external threaded portion 20 b. The external threaded member 20 b can be integrally formed into the outer peripheral wall of the intermediate member 16 a.

The body 10 b of the multi-microneedle device 10 can be formed separately from the intermediate member 18 a, followed by fixing the body 10 b of the multi-microneedle device 10 to the intermediate member 18 a by a known fixing structure including, for example, an adhesive, a snap engagement, or a fixing screw. Alternatively, the multi-microneedle device 10 and the intermediate member 18 a may be formed concurrently in an integrated manner.

Specifically, the external threaded portion 20 b of the present embodiment is provided to the outer peripheral wall of the fluid injector 12 via the intermediate member 18 a and the multi-microneedle device 10.

The peripheral wall of the outer cylinder 16 has an outer surface which is provided with a rotational operation member 16 e at a position distanced from the one-end opening 16 a toward the other-end opening 16 b. The rotational operation member 16 e assists the operation for rotating the outer cylinder 16 relative to the fluid injector 12, about the longitudinal center line of the outer cylinder 16.

In the present embodiment, the operation tool 14 is further provided with a fluid injector retention cylinder 22 which is disposed in a portion of the outer surface of the peripheral wall of the outer cylinder 16, the portion being distanced from the one-end opening 16 a toward the other-end opening 16 b of the outer cylinder 16 (a portion further distanced toward the other-end opening 16 b than the rotational operation member 16 d in the present embodiment). The fluid injector retention cylinder 22 is permitted to be rotatable together with the fluid injector 12 about the longitudinal center line of the outer cylinder 16 and also movable in a direction along the longitudinal center line, relative to the outer surface of the peripheral wall of the outer cylinder 16.

More specifically, the fluid injector 12 and the intermediate member 18 a are further protruded outward along the longitudinal center line of the outer cylinder 16 than the other-end opening 16 b of the outer cylinder 16. Similar to the fluid injector 12 and the intermediate member 18 a, the fluid injector retention cylinder 22 is also further protruded outward along the longitudinal center line of the outer cylinder 16 than the other-end opening 16 b of the outer cylinder 16.

The intermediate member 18 a has an outer peripheral surface from which at least one engagement projection 18 b is projected radially outward relative to the longitudinal center line of the fluid injector 12, being positioned in the vicinity of an end face on an opposite side of the multi-microneedle device 10 b.

The fluid injector retention cylinder 22 has an end face on an opposite side of the outer cylinder 16, the end face being formed with at least one fitting groove 22 a extended along the longitudinal center line of the fluid injector retention cylinder 22. As shown in FIG. 1, the at least one engagement projection 18 b of the intermediate member 18 a is fitted to the at least one fitting groove 22 a of the fluid injector retention cylinder 22. Accordingly, the fluid injector retention cylinder 22 is made movable relative to the outer cylinder 16 along the longitudinal center line of the outer cylinder 16 and also rotatable about the longitudinal center line of the outer cylinder 16, integrally with the intermediate member 18 a and the fluid injector 12.

The fluid retention barrel 12 b of the fluid injector 12 (syringe barrel of a syringe) connected to the multi-microneedle device 10 has an other end portion which is protruded, together with the piston member 12 c, into an external space from the other-end opening of the intermediate member 18 a.

In the present embodiment, it is preferable that each of the fluid injector retention cylinder 22, the outer cylinder 16, the intermediate member 18 a, and the fluid retention barrel 12 b of the fluid injector 12 (syringe barrel of a syringe) is formed of a transparent material so as to enable visual recognition of the amount of a fluid (medicinal solution in the medical field) retained by the fluid retention barrel 12 b, from outside the fluid injector retention cylinder 22 and the outer cylinder 16. Each of the fluid injector retention cylinder 22 and the outer cylinder 16 may be formed of a transparent material only in a portion of the outer peripheral wall that corresponds to the fluid retention barrel 12 b of the fluid injector 12.

Referring now to FIGS. 1 and 2, hereinafter is described a procedure of injecting a fluid (e.g., medicinal solution) retained by the fluid injector 12, which uses the multi-microneedle device 10, into a desired portion of a skin tissue of the exposed skin of an organism (e.g., human being in the present embodiment) by operating the fluid injector 12 by means of the operation tool 14 which is based on the foregoing embodiment.

First, a user of the operation tool 14, which is based on the foregoing embodiment, holds the fluid injector retention cylinder 22 and detachably mounts the fluid outlet nozzle 12 a of the fluid retention barrel 12 b of the fluid injector 12 to the outlet nozzle mounting nozzle 10 a of the multi-microneedle device 10. This mounting is conducted while the multi-microneedle device 10 is located at the first position, as shown in FIG. 1, by the rotation-linear movement conversion mechanism 20 of the selective movement mechanism 18.

In this case, the plurality of microneedles 10 c of the multi-microneedle device 10 which is located at the first position as mentioned above can be protected by a cap, not shown, from breakage that would be caused by an external force. The cap is detachably provided over a one-end portion in which the one-end opening 16 a is open in the outer surface of the peripheral wall of the outer cylinder 16.

The fluid retention barrel 12 b of the fluid injector 12 is already filled with a fluid (e.g., medicinal solution) to be injected into the skin tissue of an organism (e.g., human being). After removing the cap, not shown, the piston member 12 c is slightly pushed to discharge the fluid retained by the fluid retention barrel 12 b into the fluid retention space of the body 10 b of the multi-microneedle device 10 and the microscopic fluid injection channels of the plurality of microneedles 10 c of the multi-microneedle device 10. Thus, the space and the channels are filled with the fluid.

After that, keeping the state of holding the fluid injector retention cylinder 22, the user presses, as shown in FIG. 1, the skin contact surface 16 d in one-end face of the outer cylinder 16 against an exposed skin SK at a desired position of an organism (e.g., human being).

In this case, the exposed skin SK at the desired position is pushed inward by the skin contact surface 16 d of the one-end face of the outer cylinder 16.

The multi-microneedle device 10 in this case is at the first protruding position with the plurality of microneedles 10 c being externally protruded by the first distance from the one-end opening 16 a of the outer cylinder 16. As shown in FIG. 1, these microneedles 10 c are then reliably thrust into the exposed skin SK at the desired position, the skin SK being pushed by the skin contact surface 16 d of the one-end face of the outer cylinder 16 and residing in the area enclosed by the one-end opening 16 a of the one-end face of the outer cylinder 16.

In this case, the skin tissue in the area at the desired position of the exposed skin SK is in a state of having lost the elasticity to some extent.

Then, while the fluid injector retention cylinder 22 is being held, the rotational operation member 16 e of the outer cylinder 16 is operated for rotation by a predetermined amount of rotation in a given rotation direction. Thus, as shown in FIG. 2, the rotational-linear movement conversion mechanism 20 of the selective movement mechanism 18 causes outward movement to the fluid injector 12 fixed to the multi-microneedle device 10, the intermediate member 18 a fixed to the fluid injector 12 via the multi-microneedle device 10, and the fluid injector retention cylinder 22 fitted to the intermediate member 18 a as mentioned above, relative to the outer cylinder 16 from the desired position of the surface of the skin SK by a predetermined distance along the longitudinal center line of the outer cylinder 16.

In order to enable easy visual recognition of the predetermined distance from outside the operation tool 14, the peripheral wall of the outer cylinder 16 may be calibrated in the outer surface thereof, covering a range in which an end face of the fluid injector retention cylinder 22 moves, the end face being on the side of the outer cylinder 16.

As a result, the fluid injector 12 can be moved to the second protruding position at which the plurality of microneedles 10 c of the multi-microneedle device 10 are protruded to the external space by the second distance, which is shorter than the first distance shown in FIG. 1, from the one-end opening 16 a of the outer cylinder 16.

In this way, the multi-microneedle device 10 is moved from the first protruding position shown in FIG. 1 to the second protruding position shown in FIG. 2. With this movement, the plurality of microneedles 10 c are protruded by the second distance, which is shorter than the first distance, from the one-end opening 16 a of the outer cylinder 16.

At the desired position of the exposed skin SK, the plurality of microneedles 10 c of the multi-microneedle device 10 that has been moved to the second protruding position, weaken the pressing force in the area enclosed by the one-end opening 16 a of the outer cylinder 16. Then, restoring the elasticity, the skin in the area subserviently moves with the plurality of microneedles 10 c. As a result of the movement, as shown in FIG. 2, the thrust of the plurality of microneedles 10 c in the area is still maintained.

While the multi-microneedle device 10 is held at the second protruding position as described above and shown in FIG. 2, the user presses the piston member 12 c of the fluid injector 12. As a result, the fluid that has been filled in the fluid retention barrel 12 b of the fluid injector 12, the fluid retention space of the body 10 b of the multi-microneedle device 10, and the microscopic fluid injection channels of the plurality of microneedles 10 c as mentioned above can be easily and promptly injected, as indicated by the plurality of arrows in FIG. 2, into the skin tissue without leaking the fluid out of the skin SK, in the area at the desired position of the exposed skin SK that has restored the elasticity as mentioned above.

In the case where a transparent material is used for forming the fluid injector retention cylinder 22 of the operation tool 14, the outer cylinder 16, the intermediate member 18 a, and the fluid retention barrel 12 b of the fluid injector 12, the user can easily visually recognize the amount of injection of the fluid via the fluid injection retention cylinder 22, the outer cylinder 16, and the intermediate member 18 a of the operation tool 14, and the fluid retention barrel 12 b of the fluid injector 12.

In this way, the fluid can be injected from the fluid injector 12 into the skin tissue in the area at the desired position of the exposed skin SK, via the plurality of microneedles 10 c of the multi-microneedle device 10. After completing injection, the operation tool 14 is pulled apart from the desired position of the exposed skin SK. Concurrently with this, the plurality of microneedles 10 c of the multi-microneedle device 10 are pulled away from the skin tissue in the area at the desired position of the exposed skin SK.

In the foregoing embodiment, the user has pressed the piston member 12 c externally exposed from the fluid injector 12 during the period when the plurality of microneedles 10 c of the multi-microneedle device 10 are maintained at the second protruding position as shown in FIG. 2. However, the pressing of the piston member 12 c during this period can be alternatively conducted by a fluid injector selective drive unit 30 shown in FIGS. 1 and 2.

Such a fluid injector selective drive unit 30 can be detachably fixed to a portion in the outer peripheral surface of the fluid injector retention cylinder 22 or the intermediate member 18 a, the portion being opposite to the multi-microneedle device 10. Being fixed in this way, the fluid injector selective drive unit 30 is configured to selectively press an externally exposed end of the piston member 12 c as described above. Such a configuration may include a drive member, not shown, which is brought into contact with the externally exposed end of the piston member 12 c, a biasing force source, not shown, that is provided to the drive member and exerts a biasing force toward the external exposed end of the piston member 12 c, and a switch mechanism that allows the biasing force source, not shown, to selectively generate a biasing force.

More specifically, for example, the biasing force source, not shown, can be selected from a compressing spring, or a tension spring, or an elastic material, or a source of supply of compressed gas including compressed air. Further, the switch mechanism can include a known latch mechanism, or a trigger type disengagement mechanism, or a push clasp type disengagement mechanism, which stops the movement of the drive member, not shown, resisting the biasing force from the biasing force source, not shown, or can include a manually or electromagnetically driven on-off valve which is able to selectively supply compressed gas that contains compressed air from a source of supply to the drive member, not shown.

Modification

Referring now to FIGS. 3 and 4, hereinafter is described a modification of the operation tool 14 according to the first embodiment shown in FIGS. 1 and 2.

Most of the configuration of an operation tool 14′ of a first modification is similar to most of the configuration of the operation tool 14 according to the first embodiment shown in FIGS. 1 and 2. Accordingly, in the operation tool 14′ of the modification shown in FIGS. 3 and 4, the components similar to those of the operation tool 14 according to the first embodiment shown in FIGS. 1 and 2 are designated with the same references, and detailed description of these components is omitted.

The operation tool 14′ of the modification is different from the operation tool 14 according to the first embodiment in the length of an outer cylinder 16′ along its longitudinal center line.

The body 10 b of the multi-microneedle device 10 has a surface (hereinafter referred to as a tip surface) 10 d from which the plurality of microneedles 10 c are protruded. In the present modification, the length of the outer cylinder 16′ along its longitudinal center line is configured to satisfy the following. In the configuration, as shown in FIG. 3, the fluid injector 12, when it is located at a first protruding position in the fluid injector housing space 16 c of the outer cylinder 16′, the plurality of microneedles 10 c of the multi-microneedle device 10 are externally protruded from the one-end opening 16 a of the outer cylinder 16′ by a first distance. While the fluid injector 12 is located at the first protruding position, the one-end opening 16 a of the outer cylinder 16′ is positioned inward relative to the tip surface 10 d of the multi-microneedle device 10, in a direction along the longitudinal center line of the outer cylinder 16′. Further, in the configuration, as shown in FIG. 4, the fluid injector 12, when it is located at a second protruding position in the fluid injector housing space 16 c of the outer cylinder 16′, the plurality of microneedles 10 c of the multi-microneedle device 10 are protruded to an external space from the one-end opening 16 a of the outer cylinder 16′ by a second distance which is shorter than the first distance shown in FIG. 3. While the fluid injector 12 is located at the second protruding position, the one-end opening 16 a of the outer cylinder 16′ is positioned either being flush with or being protruded outward, relative to the tip surface 10 d of the multi-microneedle device 10, in the direction along the longitudinal center line of the outer cylinder 16′.

In FIG. 4, the fluid injector 12 is located in the fluid injector housing space 16 c of the outer cylinder 16′ such that the plurality of microneedles 10 c of the multi-microneedle device 10 are located at the second protruding position. While the microneedles 10 c are located at the second protruding position, the one-end opening 16 a of the outer cylinder 16′ is positioned being protruded outward relative to the tip surface 10 d of the multi-microneedle device 10, in the direction along the longitudinal center line of the outer cylinder 16′.

Referring now to FIGS. 3 and 4, hereinafter is described a procedure of injecting a fluid (e.g., medicinal solution) retained by the fluid injector 12, which uses the multi-microneedle device 10, into a desired portion of the skin tissue of the exposed skin of an organism (e.g., human being in the present embodiment) by operating the fluid injector 12 by means of the operation tool 14′ which is based on the foregoing modification.

The fluid retention barrel 12 b of the fluid injector 12, which is already filled with a fluid (e.g., medicinal solution) is detachably mounted to the outlet nozzle mounting nozzle 10 a of the multi-microneedle device 10 which is located at the first protruding position shown in FIG. 3. The piston member 12 c is slightly pushed to fill, in advance, the fluid retained by the fluid retention barrel 12 b into the fluid retention space of the body 10 b of the multi-microneedle device 10 and the microscopic fluid injection channels of the plurality of microneedles 10 c of the multi-microneedle device 10. While the fluid is being filled into the fluid retention space and the microscopic fluid injection channels, the user, in a state of holding the fluid injection retention cylinder 22, presses the tip surface 10 d of the multi-microneedle device 10, as shown in FIG. 3, against the exposed skin SK at a desired position of an organism (e.g., human being).

As a result, the plurality of microneedles 10 c of the multi-microneedle device 10 are reliably and deeply thrust into the exposed skin SK at the desired position of the organism (e.g., human being). In this case, the exposed skin SK at the desired position is pressed inward by the tip surface 10 d of the body 10 b of the multi-microneedle device 10.

Then, while the fluid injector retention cylinder 22 is being held, the rotational operation member 16 e of the outer cylinder 16′ is operated to rotate the outer cylinder 16′ by a predetermined amount of rotation in a given rotation direction. Thus, as shown in FIG. 4, the rotational-linear movement conversion mechanism 20 of the selective movement mechanism 18 causes outward movement to the fluid injector 12 fixed to the multi-microneedle device 10, the intermediate member 18 a fixed to the fluid injector 12 via the multi-microneedle device 10, and the fluid injector retention cylinder 22 fitted to the intermediate member 18 a as mentioned above, from the desired position of the surface of the skin SK by a predetermined distance along the longitudinal center line of the outer cylinder 16′.

In order to enable easy visual recognition of the predetermined distance from outside the operation tool 14′, the peripheral wall of the outer cylinder 16′ may be calibrated in the outer surface thereof, covering a range in which an end face of the fluid injector retention cylinder 22 moves, the end face being on the side of the outer cylinder 16.

As a result, the fluid injector 12 can be moved to the second protruding position at which the plurality of microneedles 10 c of the multi-microneedle device 10 are protruded to the external space by the second distance, which is shorter than the first distance shown in FIG. 3, from the one-end opening 16 a of the outer cylinder 16′.

At the desired position of the exposed skin SK, the plurality of microneedles 10 c of the multi-microneedle device 10, which have been moved to the second protruding position, weaken the pressing force in the area enclosed by the one-end opening 16 a of the outer cylinder 16′. Then, restoring the elasticity, the skin in the area subserviently moves with the plurality of microneedles 10 c. As a result of the movement, as shown in FIG. 4, the thrust of the plurality of microneedles 10 c in the area is still maintained.

While the multi-microneedle device 10 is held at the second protruding position as described above and shown in FIG. 4, the user presses the piston member 12 c of the fluid injector 12. As a result, the fluid that has been filled in the fluid retention barrel 12 b of the fluid injector 12, the fluid retention space of the body 10 b of the multi-microneedle device 10, and the microscopic fluid injection channels of the plurality of microneedles 10 c as mentioned above can be easily and promptly injected, as indicated by the plurality of arrows in FIG. 4, into the skin tissue without leaking the fluid out of the skin SK, in the area at the desired position of the exposed skin SK that has restored the elasticity as mentioned above.

In the case where a transparent material is used for forming the fluid injector retention cylinder 22 of the operation tool 14′, the outer cylinder 16′, the intermediate member 18 a, and the fluid retention barrel 12 b of the fluid injector 12, the user can easily visually recognize the amount of injection of the fluid via the fluid injection retention cylinder 22 of the operation tool 14′, the outer cylinder 16′, the intermediate member 18 a, and the fluid retention barrel 12 b of the fluid injector 12.

In this way, the fluid can be injected from the fluid injector 12 into the skin tissue in the area at the desired position of the exposed skin SK via the plurality of microneedles 10 c of the multi-microneedle device 10. After completing injection, the operation tool 14′ is pulled apart from the desired position of the exposed skin SK. Concurrently with this, the plurality of microneedles 10 c of the multi-microneedle device 10 are pulled away from the skin tissue in the area at the desired position of the exposed skin SK.

In the foregoing modification as well, the user has pressed the piston member 12 c externally exposed from the fluid injector 12 during the period when the plurality of microneedles 10 c of the multi-microneedle device 10 are maintained at the second protruding position as shown in FIG. 4. However, the pressing of the piston member 12 c during this period can be alternatively conducted by the fluid injector selective drive unit 30 shown in FIGS. 3 and 4, similar to the first embodiment shown in FIGS. 1 and 2.

In each of the operation tool 14 of the first embodiment described referring to FIGS. 1 and 2, and the operation tool 14′ of the modification described referring to FIGS. 3 and 4, the external threaded portion 20 b of the rotational-linear movement conversion mechanism 20 is not directly formed in the outer peripheral surface of the fluid retention barrel 12 b of the fluid injector 12, but, instead, is formed in the outer surface of the intermediate member 18 a which is fixed to the fluid retention barrel 12 b via the multi-microneedle device 10 to which the fluid retention barrel 12 b is detachably connected. However, according to the concept of the present invention, the intermediate member 18 may be omitted, as a matter of course, to directly form the external threaded portion 20 b of the rotational-linear movement conversion mechanism 20 on the outer peripheral surface of the fluid retention barrel 12 b of the fluid injector 12.

In this case, the fitting groove 22 a of the fluid injector retention cylinder 22 may be configured such that a finger flange at the other end of the outer peripheral wall of the fluid retention barrel 12 b of the fluid injector 12 is fitted to the fitting groove 22 a. With this configuration, the fluid injector retention cylinder 22 can be moved along the longitudinal center line of the fluid retention barrel 12 b (i.e. the longitudinal center line of the outer cylinder 16) or can be rotated about the longitudinal center line, integrally with the fluid retention barrel 12 b of the fluid injector 22.

Further, use of the rotational-linear movement conversion mechanism 20 enables control over the thrust depth of the plurality of microneedles 10 c of the multi-microneedle device 10 with respect to the desired position of the skin SK in terms of a millimeter unit or a sub-millimeter unit.

When intradermal injection is conducted by means of a syringe that uses a multi-microneedle device, a fluid (e.g., medicinal solution) to be used for the intradermal injection is charged in advance into the syringe barrel of the syringe via the fluid outlet nozzle of the syringe barrel. Then, the outlet nozzle mounting nozzle of the multi-microneedle device is detachably mounted to the fluid outlet nozzle of the syringe barrel. After that, the piston member of the syringe is slightly pushed to push the air in the fluid retention space of the multi-microneedle device and in the individual microscopic fluid injection channels of the plurality of microneedles out of the syringe barrel, thereby filling the fluid in the fluid retention space and the microscopic fluid injection channels of the plurality of microneedles of the multi-microneedle device.

Then, the skin contact surface of the body of the multi-microneedle device is pressed against a desired portion of an exposed skin of an organism (e.g., human being). With this pressing, the plurality of microneedles on the skin contact surface are thrust into the skin tissue in the desired portion of the exposed skin of the organism (e.g., human being). When the piston of the syringe is pushed subsequently, the fluid from the syringe barrel is injected into the skin tissue in the desired portion of the exposed skin of the organism (e.g., human being) via the fluid retention space and the microscopic fluid injection channels of the plurality of microneedles of the multi-microneedle device.

When intradermal injection is conducted by means of a syringe that uses a multi-microneedle device, the piston member of the syringe is pushed, in a state where the skin contact surface of the body of the multi-microneedle device is pressed against a desired portion of the exposed skin of an organism (e.g., human being). In this case, the desired portion of the exposed skin is loaded with not only a pressure from the skin contact surface of the body of the multi-microneedle device, but also a force of pressing the piston of the syringe. As a result, the skin tissue in the desired portion of the exposed skin loses elasticity to some extent. For this reason, not all of the fluid (e.g., medicinal solution) can be injected from the plurality of microneedles into the desired portion of the skin tissue when intradermal injection is conducted by means of a syringe that uses a multi-microneedle device. Therefore, the fluid is leaked onto the surface of the desired portion of the skin, or comparatively a long time is taken for injecting all of a desired amount of the fluid into the skin tissue in the desired portion.

The present invention has been made in light of the circumstances set forth above and has as its object to provide an operation tool, i.e. an instrument for operating a fluid injector that uses a multi-microneedle device, which easily and reliably enables any person to inject, in a short time, all of a desired amount of a fluid in a fluid injector, such as a syringe, that uses the multi-microneedle device, into a skin tissue in a desired portion, in conducting intradermal injection in the skin tissue in the desired portion by means of the fluid injector, and which can be simply configured at low cost.

In order to achieve the object of the invention mentioned above, an instrument for operating a fluid injector that uses a multi-microneedle device, according to a concept of the present invention, that is, an operation tool for a fluid injector that uses a multi-microneedle device, is characterized in that the instrument includes:

an outer cylinder that has a one-end opening and an other-end opening, and a fluid injector housing space that extends between the one-end opening and the other-end opening and movably holds the fluid injector that uses the multi-microneedle device, along a longitudinal center line of the fluid injector; and a selective movement mechanism that moves the fluid injector between a first protruding position and a second protruding position in the fluid injector housing space of the outer cylinder, the first protruding position allowing a plurality of microneedles of the multi-microneedle device to protrude to an external space by a first distance from the one-end opening of the outer cylinder, the second protruding position allowing the plurality of microneedles of the multi-microneedle device to protrude the external space by a second distance that is shorter than the first distance from the one-end opening of the outer cylinder, wherein:

a fluid is discharged at the second protruding position from the fluid injector via the plurality of microneedles of the multi-microneedle device; and the selective movement mechanism includes a rotational-linear movement conversion mechanism that is interposed between the outer cylinder and the fluid injector, and moves the fluid injector between the first protruding position and the second protruding position along a longitudinal center line of the outer cylinder, in conformity with a direction and amount of rotation of the outer cylinder relative to the fluid injector.

In the instrument for operating a fluid injector that uses a multi-microneedle device, according to a concept of the present invention characterized by the above configuration:

The fluid injector is moved between the first protruding position and the second protruding position by means of the selective movement mechanism. In this case, the fluid injector that uses the multi-microneedle device is movably held in the fluid injector housing space extending between the one-end opening and the other-end opening of the outer cylinder, along the longitudinal center line of the fluid injector. The first protruding position allows the plurality of microneedles of the multi-microneedle device to protrude to an external space by a first distance from the one-end opening of the outer cylinder. The second protruding position allows the plurality of microneedles of the multi-microneedle device to protrude to the external space by a second distance, which is shorter than the first distance, from the one-end opening. Thus, at the second protruding position, the fluid is discharged from the fluid injector via the plurality of microneedles of the multi-microneedle device.

The first protruding position can contribute to well thrusting the plurality of microneedles of the multi-microneedle device into a skin tissue at the desired position.

In this case, the plurality of microneedles of the multi-microneedle device applies a pressing force to the exposed skin at a desired position of an organism and the pressing force impairs the elasticity of the exposed skin at the desired position.

Then, the second protruding position can contribute to mitigating the pressing force applied by the plurality of microneedles of the multi-microneedle device to the exposed skin at the desired position of the organism. In other words, the elasticity is restored in the skin tissue of the exposed skin at the desired position. This tendency is more emphasized when the one-end opening of the outer cylinder is in contact with the exposed skin at the desired position.

Then, at the second protruding position, the fluid is discharged from the fluid injector via the plurality of microneedles of the multi-microneedle device. Thus, the fluid discharged from the plurality of microneedles is promptly injected into the skin tissue of the exposed skin at the desired position of the organism.

Moreover, by operating the selective movement mechanism, anyone can easily and reliably move the fluid injector that uses the multi-microneedle device, from the first protruding position to the second protruding position relative to the outer cylinder.

The instrument for operating a fluid injector that uses a multi-microneedle device is based on the invention characterized by the configuration as described above. Using such an instrument, when conducting intradermal injection in a skin tissue at a desired position by means of a fluid injector, such as a syringe, anyone can easily and reliably inject, in a short time, all of a desired amount of a fluid in the fluid injector into the skin tissue at the desired position. In addition, the selective movement mechanism includes the rotational-linear movement conversion mechanism which is interposed between the outer cylinder and the fluid injector to move the fluid injector from the first protruding position to the second protruding position along a longitudinal center line of the outer cylinder, in conformity with the direction and amount of the rotation of the outer cylinder relative to the fluid injector.

Such a selective movement mechanism can be provided at low cost with a simple configuration.

DESCRIPTION OF REFERENCE NUMERALS

10 . . . Multi-microneedle device, 10 a . . . Outlet nozzle mounting nozzle, 10 b . . . Body, 10 c . . . Microneedles, 10 d . . . Tip surface, 12 . . . Fluid injector, 12 a . . . Fluid outlet nozzle, 12 b . . . Fluid retention barrel, 12 c . . . Piston member, 14 . . . Operation tool, 16 . . . Outer cylinder, 16 a . . . One-end opening, 16 b . . . Other-end opening, 16 c . . . Fluid injector housing space, 16 d . . . Skin contact surface, 16 e . . . Rotational operation member, 18 . . . Selective movement mechanism, 18 a . . . Intermediate member, 18 b . . . Engagement projection, 20 . . . Rotational-linear movement conversion mechanism, 20 a . . . Internal threaded portion, 20 b . . . External threaded portion, 22 . . . Fluid injector retention cylinder, 22 a . . . Fitting groove, SK . . . Skin;

14′ . . . Operation tool, 16′ . . . Outer cylinder

Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein. 

What is claimed is:
 1. An injection method, comprising: thrusting, to a first depth in skin, a plurality of microneedles of a multi-microneedle device of an operation tool having a fluid retention body including a fluid; moving from the first depth to a second depth in the skin while the microneedles are thrust in the skin; injecting the fluid in the fluid retention body into the skin through the microneedles; and taking the microneedles out of the skin.
 2. The injection method of claim 1, wherein each of the microneedles has a height in a range of from 100 μm to 2000 μm.
 3. The injection method of claim 1, wherein the moving is conducted by a rotational-linear movement conversion mechanism.
 4. The injection method of claim 2, wherein the moving is conducted by a rotational-linear movement conversion mechanism.
 5. The injection method of claim 1, wherein the moving is along a direction in which the thrusting is conducted.
 6. The injection method of claim 2, wherein the moving is conducted by a rotational-linear movement conversion mechanism.
 7. The injection method of claim 3, wherein the moving is along a direction in which the thrusting is conducted.
 8. The injection method of claim 4, wherein the moving is along a direction in which the thrusting is conducted.
 9. The injection method of claim 1, wherein the first depth is deeper in the skin than the second depth.
 10. The injection method of claim 2, wherein the first depth is deeper in the skin than the second depth.
 11. The injection method of claim 3, wherein the first depth is deeper in the skin than the second depth.
 12. The injection method of claim 4, wherein the first depth is deeper in the skin than the second depth. 